Yeah i'm glad it didn't happen when i was moving! i'd probably have eaten the steering wheel!

no thrust block... that we saw....maybe it used to be all the metal shavings we found  

Congrats and HUGE KUDOS to you for posting a follow-up!

Threads like these are tremendously valuable for future users and it is incredibly frustrating to be someone who finds a thread that details the identical problem they are experiencing but then there is no resolution or follow up post.


I worked on a friend's car once that had the same issue-- the carrier wallowed out and the diff pin came out. Only for him, it happened while on a drive and he exploded his transmission case as the pin fell out while moving.

Does your stock diff have a thrust block in it or is it one of the later ones where they stopped using it? Can anyone explain why they stopped using the thrust block?

Good to know it WASN'T a loose shift fork or other mentioned transmission woes.

OK here is the update!  And the winner/loser is a bad carrier on the housing caused the diff pin to fall out and the planetaries to come lose and got binded up in there.. 

The carrier looked more like an oval than anything resembling a circle. I guess the differential pin banged around in there until the lock pin fell out and then it successfully made its escape from the housing. Its probably been wallered for quite some time which probably explains the clunk i heard as i shifted gears. The last time i parked it i probably happened to stop with housing in the up and down position and that was it!

So i ordered a new upgraded cross pin unit and hopefully wont happen again any time soon!
Thanks everyone! 

We have a winner!  Dan has it!  Very unusual but has happened recently... I posted similar symptoms a few weeks ago!

You only 'think' you in neutral!  I bet the car will actually drive in the gear that is engaged, despite what the shifter thinks! Put it in "neutral" so only one gear is engaged.  you can figure out which 'gate' (1st & 2nd or 3rd & 4th) has a slipped shift fork because the car will drive in that gate.  But when you try to engage another gear. It locks up!   This happened while driving on a down shift into 2nd, and resulted in tearing up the inner yokes and couplers for someone I know!

If this is indeed the case, it must come apart to fix it!

The differential will allow each front wheel to rotate independently of one another when the car is in the air, both wheels off the ground. 

You've confirmed that the issue isn't with an axle or wheel related since each one will rotate. I think it is safe to say that it isn't a diff pin, either.

Try it again with one front wheel on the ground and one in the air (and the rear wheels on the ground and chocked! Basically, get a jack under the bottom suspension arm and jack it enough to get it off the ground. Try to spin the wheel and listen very very carefully for a little metal "tick" sound of maybe 1 ball bearing ticking into another. It's a delicate sound but you can hear it if you listen carefully. You may need to do several wheel locations. But do it slowly. When the car is at rest, all of the ball bearings bunch up and fall down and when hit with hight torque, the shaft will find that weak spot where there are no bearings and push into that void. Doing this tranny rotation test with either 1 wheel on ground or a partner holding one well still while both are off the ground will allow one loose bearing at a time to crawl up the race and then fall down against the ones at rest at the bottom. Keep rotating slowly and you'll hear the one at a time Click/Tick down as they climb and fall. Doing this with the engine oil drained can help.

If you've found nothing discernible with this tranny rotation check, the next this is while it is still with one wheel in the air, put car in 4th gear, engine off.  While turning the wheel it should also try to rotate the engine. It will be difficult but not impossible. If you pull the spark plugs, it could be a little easier. If you can get a full revolution or two out of the wheel, then it tells me that it could still be the double roller bearing that I and CTR refer to. Under high torque the force will just push that mainshaft wonky but under hand pressure, it could still complete a full rotation.



Good luck. But regardless, sounds like an engine out deal.

You may get lucky and it's bad engine steadies and you'll see the engine try to rock while doing the tranny/engine rotation test which could be pulling our gear lever partially out of gear.

@coopertune
No idea what the casting on the tranny is i'll have to look.

@Alex
The motor will stall if i try to disengage the clutch once in either first or rev.
wheels all rotate when off the ground.. 

I have it over at my buddies now we are looking into the next steps which presumably is pulling out the tranny since this seems like its not a simple "oh, just tighten this bolt and your good to go"   

You don't mention what casting number the tranny is. I have suffered a whole lot with late DAM 5626 trannys seems the main shaft ball bearing spacers are plastic and break up allowing all ball to fall to one side and the gears move apart and start popping teeth. I have had them so bad that they blow a hole in the bottom of the case. Most of the time if taken apart before a complete failure the case is bad any way due to the main shaft bearings moving around in the case bores. I have lost 5 cases to this problem two with holes in them and three with damaged bearing bores. 

The other thing I run into now and then is the diff pin breaking in two. The end that is not pinned to the cage slides out of diff cage and fouls the tranny case acting much like you describe. I don't expect it to be a self healing issue. Steve (CTR)

? Shifter fork loose on shift rail allowing 2 gears to be engaged?

Bolt for crown wheel loose or came out and stopping rotation?

Does the engine stall when you try and drive it ?

Can you rotate all four wheels with them off the ground ?

Does sound like something in the diff or gearbox, but try and eliminate something daft like a loose brake shoe or similar first.

Sounds like double roller bearing in the transmission lost it's cage and mainshaft is pushing/binding. Admittedly, that's an extreme diagnosis, but exactly what's happened to me a couple times before.

Hopefully yours is something more simple.

Ok so i have a very odd issue. I have a 1980 with a 1098. I parked the car was runing driving fine. next morning i go to move it and it won't roll so i did some testing here are the symptoms:

Car flat on ground. In neutral-
   -moves about a 1/8 turn then clunks and stops. 
   -Same pushing it backwards
Jacked up rear of the car both wheels spin freely -not an e-brake issue
Jacked up front of car. each wheel spins (one forward one back)

with car jacked up i turn on motor and put it in gear as i let out the clutch same problem i get about an 1/8 of a turn than nothing.
If i put it in reverse i get that 1/8 of a turn back. and i can do that forward and back but still no further than that in either direction.

I'm stumped.